class Solution {
public:
    stack<int> s1;
    stack<int> s2;
    void push(int value)
    {
        s1.push(value);
        if (s2.empty() || s2.top() > value)
            s2.push(value);
        else
            s2.push(s2.top());
    }
    void pop()
    {
        s1.pop();
        s2.pop();
    }
    int top()
    {
        return s1.top();
    }
    int min()
    {
        return s2.top();
    }
};